In an e-mail, Swersey said the hotel where they was staying, as well as others in the city, opened their doors to the many hundreds of people who couldn't get out of Tokyo when the subway trains stopped running in the wake of the temblor.

"Most were sitting quietly in small chairs while others were on the floor but there was no sense of any panic or confusion, just stoicism," Swersey wrote of the scene.

Swersey, a professor of operational research, said the Yale group was visiting Nissan Motors about 90 minutes outside Tokyo when the largest earthquake ever recorded in Japan and the subsequent tsunami devastated parts of the country.

"We were in a conference room on the second floor. We got under the tables as a precaution and (then) left the building and assembled in the parking lot. It took us six and one half hours to return in our bus to Tokyo," Swersey said.

The deadly two-minute quake the West heard about on Thursday was actually preceded by a smaller one two days earlier when Swersey said he and the students were in a conference room on the 40th floor of the Keio Plaza and that building started swaying for a short time.

Swersey reported that the night after the 8.9-magnitude quake hit there were numerous aftershocks.

"It was unnerving as all of us were 25 stories or higher in our hotel and the building was swaying in response," he wrote of a situation not commonly experienced by Americans.

Much has been written about the strict Japanese building codes and the extra steel bracing and hydraulic shock absorbers embedded into their high-rises which is credited with saving many lives.

But there were reports that even the Japanese, who are used to swaying buildings, were frightened by the force of this temblor.

The main damage has been along the northeast coastline near the city of Sendai with the death toll expected to easily exceed 1,000.

Swersey wrote that the students were fine and that there were no plans at this point to return to the U.S. earlier than March 17. On Saturday, he said students were doing some sightseeing in Tokyo and with the train schedules returning to normal, they were planning to continue the tour with a visit to Toyota in Nagoya.